Chusetts



UNITED STATES PATENT OFFICE.

GEORGE E. BURT, ABRAM VRIGHT, AND GEORGE F. WTRIGHT, OF HARVARD, MASSA- CHUSETTS.

HORSE-POWER.

Specification of Letters Patent No. 18,232, dated September 22, 1857.

To all whom t may concern Be it known that we, GEORGE E. BURT, ABRAM VRIGHT, and GEORGE F. WRIGHT, of Harvard, in the county of lVorcester and State of Massachusetts, have invented a new and Improved Horse-Power; and we do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, making a part of this specification, Figure l being a side view of our improved horsepower; Fig. 2, a longitudinal vertical section of the same, and Fig. 3 is a diagram, which particularly illustrates the practical working of our improved horse-power and also the method by which we give an improved shape to the ends of the tracks of said machine.

Heretofore the ends of the side tracks of horse-powers have been made in the form of a semi-circle. The objections to this form of tracks for horse powers may be seen by examining Fig. 3, which illustrates by the different positions of the sections of the platform chain and wheels, also, the difliculty which exists in the above-mentioned track, and the proper shaped track, necessary to overcome that difculty.

It will be readily seen, that those sections of the platform chain represented by lines marked g, g, g, g, in Fig. 8, that the extremity of the number' of links, or sections so represented, is at 7L, and L, and the centers of the flexible joints are on the true semi-circular line at the angles of the sections, but if moved forward one half the length of a section or link, as is represented by the red lines marked z', z', z', the end of the link would only arrive at 3"; if the flexible joints of the platform were kept on the semicircular line, and the space between the lines z" and j, is the amount required by the one position over and above the other, also, the lines m, m, m, which represents the sections moved forward three-fourths of the length of a section, if the flexible joints are kept on the selni-circular line, the sections or links would only reach to fa, when with the same tension of chain, it should reach to O. Consequently there is an intermittent tightening up and loosening of the chain, caused by the varying position of the sections of the platform chain in passing around the ends of the tracks of all such horse powers, and the said motion is very much increased,

by increasing the width of the sections of the platform or chain, and it is necessary to make the chains to such horse powers, to hang loosely below the trac is. This however does not prevent a heavy tremulous motion causing a severe strain upon the machine, and exerts a wearisome and injurious effectupon the horses employed on them.

Our improvement consists in giving such a shape to the ends of the side tracks to horse powers that closely tted platform chains, of any desired width of sect-ions, can be fitted tightly to said tracks, and yet, pass over their extremities with a perfect and unvarying smoothness, not embracing the track more tightly at one point than at another.

This is shown by the exact position of the links, wheels and tracks in Fig. 3. lt will be noticed by the position of the platform sections of chain marked g, g, g, g, that the flexible joints at their angles are on the semicircular line, but when moved forward onehalf of the length of a link or section, as represented by the red lines, marked i, vi, i, the flexible joints of the sections or links come within the seini-circular line sufficiently to allow the end of the link to arrive at y', as represented.

The tension of the chain and the position of the links being equal; also, the position of the sections or links marked m, m, m, being moved forward three-fourths of the length of a link, the flexible joints come within the semi-circular line, in proportion to their position, the wheels all resting on the improved shaped track, and the ends of the links meeting at their proper point-s, as represented,thus obviating all unequal strain or motion.

The rule by which we unerringly obtain the improved shape of the end of the track of our horse power, is as follows, viz: We first strike a semi-circle whose chord is the desired diameter of the orbit of the flexible joints of the chain, and divide the said semicircle into two equal parts; we then ascertain what is one-seventieth part of the chord of either division of the said semi-circle, and project diametrical lines through the centers of each of the aforesaid divisions, and make dots on the diametrical lines, just the aforesaid one-seventieth distance, within the semicircular line. Ve then take a suitable marking instrument and by placing it on the diametrical lines find the radius of a circle, the

are of which will embrace the extremities of the chords, and pass through the dots aforesaid, thus forming the orbit of the centers of the oint platform sections. We then strike the desired circumference of the rolls, by planting the marking instrument on the centers of the flexible joints of the chain, and proceed to strike the track, by planting one point of the instrument on the diametrical line where it rested to strike the orbit of the chain joints, and find the radius of a circle which reach the circumference line of the wheels or rolls, and form the arc which is the proper shape of the end of the track of our improved horsepower, when two sections of the chain cover the end of the orbit, but when it is desired to have a greater number of sections of the platform, contained in the end of the orbit of said chain, the end of the tracks are formed by the same rule above laid down with the following additions, to wit: 7e divide the semi-circle into as many divisions as desired and project diametrical lines through the centers of the outermost divisions, and on the said diametrical lines We plant a suitable marking instrument of the radius, of the aforesaid `orbit, or its equivalent, nineteen thirty siXths of the chord of the semi-circle aforesaid, in such a position as to embrace the extremities of the chords of the outermost division, completing the end of the orbit. 7e then strike the circumference of the rolls as aforesaid, and proceed to strike the track by planting our marking instrument on the diametrical lines,

at the same point where it rested to strike the orbit of the outermost divisions, and find the radius of a circle that will reach the cir cumference line of the wheels whose centers are at the extremities of the chords of the outermost divisions aforesaid; and having struck the arcs for these divisions, we move the resting point of our instrument to the center of the semi-circle, and find the radius of a circle which will unite the arcs of the outermost. divisions and reach the circumference lines of the wheels of the central divisions, forming a complete track on which all the wheels or rolls of the chain in the end of its orbit, rest. This rule will answer in all cases, for any number of divisions in a semi-circle, which forms the basis in laying out the shape of the ends of the tracks of our improved horse power.

Having thusv fully described our improved horse power, what we claim therein as new and desire to secure by Letters Patent is- The method by which we are enabled to unerringly give such a shape to the ends of the tracks of said machine, that closely fit-ted platform chains may be operated upon them without producing any variation of tension or irregularity in the movements of said chain, substantially as herein set forth.

GEORGE E. BURT.

ABRAM WRIGHT. GEORGE F. WRIGHT. lWitnesses SoLoN 7. JOHNSON, REUBEN lVHrrcoMB, Jr. 

